package cn.filter;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class LoginFilter implements Filter {

    
    public LoginFilter() {
      System.out.println("login filter construct!");
    }

	
	public void destroy() {
		System.out.println("destroy invoke.............");
	}

	
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		
		HttpServletRequest   req  = (HttpServletRequest) request;
		HttpServletResponse  resp = (HttpServletResponse) response;
		if(req.getSession().getAttribute("user")!=null){
			chain.doFilter(req, resp);
		}else{
			req.setAttribute("msg", "登录失败请重试");
			req.getRequestDispatcher("login.jsp").forward(req, resp);
		}
	}

	
	public void init(FilterConfig fConfig) throws ServletException {
		System.out.println("init invoke......................");
	}

}
